I'd go to my closet friends. However, I refuse to vent about marital issues with male friends. I feel that leaves open the possibility of being too emotionally close to a guy friend. And that can lead to issues (from personal experience).

Oh man, I definitely advise AGAINST going to your in-laws for advice. SO may see that as a huge betrayal and being ganged up on. Studies recently showed that men who are close with their in-laws have lower rates of divorce whereas women who are close with their in-laws have a significantly higher rate of divorce than women who are not.

Anyway, it's lame that your mom is difficult to talk to. I always talk to her or my close friend. If you ever need to vent, feel free to message me. It's been hard for me, too, because none of my friends have kids yet and most of them aren't married either (I just turned 22.)

I go to my closest friends Stacy and Racquelle or my sister. BUT I definitely hold back when I vent because I do not want my loved ones to judge my SO harshly when they only have heard my end of the story while I'm really pissed. From personal experience, my sister almost hated my SO because I would hardcore vent but in reality he isn't that bad, I was just pissed every time I vented. That's why I just keep it to myself. I do go a little crazy from it but I usually get over the issue.